Some introduced populations thrive and evolve despite the presumed loss of diversity at introduction. We aimed to quantify the amount of genetic diversity retained at introduction in species that have shown evidence of adaptation to their introduced environments. Samples were taken from native and introduced ranges of Arctotheca populifolia and Petrorhagia nanteuilii. Using microsatellite data, we identified the source for each introduction, estimated genetic diversity in native and introduced populations, and calculated the amount of diversity retained in introduced populations. These values were compared to those from a literature review of diversity in native, confamilial populations and to estimates of genetic diversity retained at introduction. Gene diversity in the native range of both species was significantly lower than for confamilials. We found that, on average, introduced populations showing evidence of adaptation to their new environments retained 81% of the genetic diversity from the native range. Introduced populations of P. nanteuilii had higher genetic diversity than found in the native source populations, whereas introduced populations of A. populifolia retained only 14% of its native diversity in one introduction and 1% in another. Our literature review has shown that most introductions demonstrating adaptive ability have lost diversity upon introduction. The two species studied here had exceptionally low native range genetic diversity. Further, the two introductions of A. populifolia represent the largest percentage loss of genetic diversity in a species showing evidence of substantial morphological change in the introduced range. While high genetic diversity may increase the likelihood of invasion success, the species examined here adapted to their new environments with very little neutral genetic diversity. This finding suggests that even introductions founded by small numbers of individuals have the potential to become invasive.

In order to determine the risk of bacteraemia from ERCP, we cultured blood specimens from 83 patients before, during and 15 min, 1, 6, 12 and 24 hours after the examination as well as in the subsequent week whenever fever occurred. No bacteraemia was found in the 20 patients who had duodenoscopy only, i.e. in whom ERCP failed. Of the 20 patients with normal biliary and/or pancreatic ducts positive culture was obtained in one patient in whom inadvertent multiple injections of contrast material into the pancreatic duct had resulted in the occurrence of a pyelogram. Four positive cultures were found amongst the 43 patients in whom an obstructive pathology in the biliary or pancreatic system was present. These data support the need of on antibiotic prophylaxis for patients with valvular heart defects.

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